Friction band



Ju e ao, '192-5.

E. R. GILL FRICTION BAND Fi-led May '7, 1923 3 Sheets-Sheet l June 30,1925. 1,543,701

E. R. GILL FRICTION BAND Filed May 7, 1925 5 Sheets-Sheet 5 SwuemiozPatented June 30, 1925.

UNITED STATES nnwnv a. GILL, or YQNKERS, new roan.

FRICTION BAND.

r 3 Application filed May 7,

To all 107mm it may 0011mm:

Be it known that I, EDWIN R. GILL, a

citizen of the United States, and a resident of Yonkers,lVestchester'County, State of New York, have invented a certainImprovement in Friction Bands, of which the following is aspecification.

The present invention relates to an im proved construction for use inany form of mechanism depending upon frictional resis tance for itsoperation. The principles underlying the invention are capable of embodiment in an indefinite number of forms, and particularly in frictionclutches whether fiat faced or of the drumtype. In a preferred form, theimprovement is particularly adapted for use in speed bands on motorcars, whether applied to the brake or to the controlof the clutchesgoverning the speed changing or stopping and starting means. lVhere usedin frictional. clutches or brakes of the drum type, the invention may beemployed. either upon the concave surface of an external clutch band orthe convex surface of an internal clutch band. The valuable propertiesof cork when used to create friction are well known, and more or lesssuccessful attempts have been made to utilize groups of cork masses forthis purpose in a. commercially satisfactory manner. The presentinvention supplies means for carrying out this endin such a manner as toovercome certain well recog nized difficulties which have heretoforebeen met with in this field. The invention also covers the use of anyfriction-producing masses which may be suitable as substitutes for cork.i

In employing cork, or its equivalent, in the production of afriction-producing surface, the cork is often used in the form of anumber of masses held in cavities or perforations in a foundation ofbrass or other suitable metal. Onedifficulty that has been encounteredin these cases is that of securing the masses firmly in place. Oneprincipal object of the present invention is the successful solution ofthis problem.

Another object of the invention is the production of means whereby thefoundation to which the cork masses are applied may be perforated andprepared to receive the cork quickly and cheaply as possible, andwithout danger of weakening or otherwise injuring it. In carrying out myinvention,

I am able topunch out all of the perfora- 1923. Serial NO. 637,107.

tions at once, by a single forward movement of a group of dies.

In order to make such an operation as this posslble, 1t is clear thatthe foundation plate must be quite thin, and indeed, I have successfullyused a foundation plate only a sixteenth of an inch thick for thispurpose. It is clear that a sheet of brass as thin as this would notserve to hold the cork masses securely, if the latter were merely driveninto the perforations. The area of contact between cork and brass wouldnot be sufficient to produce the necessary holding friction underconditions of use. Moreover a thin band of this character, used byitself, would not be strong enough to meet the conditions of practicaluse.

Accordingly my present invention comprises a composite foundationstructure, wherein a number of relatively thin metal. strips are used ina manner to re-enforce each other. The strip occupying the WOIl ing faceof the foundation or band should be made of suitable friction metal,preferably brass. Behind this is employed a similar strip of iron; andthe couple thus formed is preferably secured to an exterior strip ofsteel or other resilient metal. This last is only perforated where it isriveted to what may be called the coii'k-holding couple of frictionmetal and iron or the like.

In order to provide a perfectly secure fastening for the cork masses,consistently with i the use of thin brass plates; the middle, or iron,plate or strip is provided with perforations registering with those inthe brass strip, but made somewhat larger than these last. The corkmasses are made of such a size as to requireforcing into theperforations in the inner or brass plate, and are of a size to projectinto the perforations in the middle or iron plate, while also projectingabove the free surface of the brass plate. The portions of the corkmasses which have been thus forced through the brass plate swell as soonas they enter the larger perforations in the iron plate, and the swollenportion effectually prevents the masses from coming out of the seats orsockets thus provided.

In addition to facilitating quick and cheap manufacture, the use of thinplates has a further advantage where bands are used on friction drums.In order to place such bands in position when assembling the mechanism,they have to be opened to an abnormal extent to make it possible to passthem over their cylinders. If thick plates are used, they are liable totake on aset on a permanent moleculardisplacement, This interferes withproper fitting and impairs their resilience. This eflect is reduced to aminimum with thin plates. Where thin plates are used the dies also last'much longer than when used on thick plates.

It'is a conspicuous advantage of thisinvention that it'makes it possibleto use triction producing masses that are relatively small transverselythus increasing the total active area available. At the same time, asthe depth of each mass is great in proportion teits width, the danger ofaccidentally" forcing masses out of place is decreased.

In the accompanying drawings, Figure 1 is a side elevation of apreferred form of spring frictionband of a type useful as a speed bandfor automobiles, the samebein'g shown 111 lts normal, uncompressedoridle condition, Figure 2 is a greatly eXag-' gerated view in section ofa small portion of a composite foundation 1n flat position, Figure 3 ISa perspective view of a corkmass as used in theimproved structure, thesan'ie being shown greatly enlarged, Figures l to p of clutch operatingmechanism illustrated 6 inclusive are enlarged views or portions or theouter or steelband, the middle or non band, and the inner or brass bandor striprespectively, all shown in flat position, Fig

urer' is a similar view ofthe-se portions superposed 1n the flat andbefore being bent into final form and riveted together, and

FigureS is a'vie w in elevation of one lorm by way of example. 7

In Figure l the speed band or brake band shown is one adapted to be"used in controlling th movement of a revolving drum, and it is thereshown substantially inthe normal position, by which is meant-thepositionwhich it naturally assumes when free, and to which it tends'to return byits own resilience.

As shown in this figure, the band comprises three concentric strips,placed one over the other and secured together.' The outermost orsupporting striplt) ismade of resilient metalsuch as steel, the ends ofwhich are preferablysupplied with cars 11 and 12, of a well knowncharacter, serving for the attachment of mechanism of any suitablecharacter whereby the entire band may be more or less tightened upon therevolving drum to be controlled. i The cork holding couple, composed ofan interior strip l3and a middle strip l i, is secured to thesupportingstrip 10 by rivets 15 passing through all these strips at'suitable intervals The effective frictional gripis secured by corkmasses'16 or their equivalents, preferably cylindrical in form, asshow'ninlfligure 3, whichare secured in place as hereinafter described. It isto be understood that these masses may be of any convenient shapewithout departing from.

In preparing templates for constructing dies adapted to punch out anentire stripin. one operation; the full lengthof each strip may beconsidered forthe present purpose, as composed of substantiallysimilarsections between the successive rivet holes 17 and'lS in the outermostplat'10..

Since the various strips are separately punched while in the fiat; itisclear that the'exact location of the perforations, in tended toregister 1 when the device is in the normal curved positi oirshowninFigure 1, mustbe laid out witlr due respect to the change in theirrelative positions caused by bending them into" such normal position:Figures t "to 7 illustrate the method employed'on a scale thatis greatlyexaggerated, to makethe sameclearer to the eye. In preparing the guidingtemplates, similai sections of whichare shown in' these figures, thepositioir otriveting holes are first accurately ascertained on all threestrips whilein thenormal curved position. hen the strip. templates arethen straightened and the-fiat strips are compared with end holes'atone'end"of all three coinciding, the"positions ofthe other rivetholes willbefoundlo beout ofregistry' to a progressively greater extent, measuringaway fromthe coinciding holes. This is illustrated'for the firstsectionin Figures 4" to 7 wherein the hole 17 in the steel plate 10igure 4) coincides with the dotted circle I'F 'in the middle'orironstrip 14 '(Figuret) and thehole 17" inthe brass strip 13 (Figureti;while at the opposite end of the first" section, the dotted circle 1Slll' lllle strip. Hand, the circle 18? in the strip 15 represent thepositionsof the holes througlrwhich the next rivet passes. As thereshown the distance from 17 to 18 'is shorterthan from 17 to 18, and thedistance fronrlfr to 18 is still' shorter. This" is due to the'tact thatthe total length of the strip 14 is somewhat less when straightened outthan that of the strip 10, and. that the strip 13 is correspondinglyshorter than the strip 14.

The respective positions of the rivet holes in the three strips beingknown, the next step is to lay out themiddle row of perforations 19 inthe middle or iron strip 11-, so that a perforation at one end of thesection shall be concentric with the position 17 and another at theopposite end of the section shall be concentric with the position 18";and that the intermediate perforations, all of the same size, shall beequally spaced. This being done, the other two rows of perforations, 20and 21, are similarly laid out, taking care that the transverse linesjoining the centers ofperforations in the two side rows shall cross theline of centers of the middle row half way between centers. The idealhexagonal arrangement of perforations is thus attained in the middlestrip 14, and the maximum proportion of cork area is secured.

The same procedure can then be followed with respect to the innermost,or brass, strip 13 (Figure 6) taking care that the longitudinal lines ofcenters of the three rows in the strip 13 are the same distance apart asthose in the strip 14. The distances apart measured longitudinally.between the centers of perforations 22, 23 and 2a respectively on theinnermost strip 13, will, however, be less than that betweencorresponding centers on the middle strip 1-1. The perforations on thestrip 13 are also somewhat smaller than those in the strip 14: for thereasons already explained.

When the three templates have been thus prepared, their appearance assuperposed flat, with the brass plate 13 next the observer will be asillustrated on an exaggerated scale in Figure 7. hen bent into thenormal form shown in Figure 1, however, the centers of all holes will bein substantial registry. Accordingly if strips be punched from dies madeaccording to such templates, they can be riveted together in the mannershown in Figures land 2, and the inner cork holding couple e111 presentrows of openings in the friction plate 13, each of which is backed up bya concentric opening made somewhat larger in the middle or iron plate14. hen the cork masses 16 are forced through the friction plate 13,they will swell out within the enlarged space afforded by the openingsin the iron plate, being thus secured from accidental removal. This isplainly shown on an exaggerated scale in Figure 2.

In this figure is also shown a preferred detail of construction, namelythe cupping or swaging inward of the brass or friction plate 13 aroundthe rivet holes, as shown at 25. The conical projection thus formed fitsinto the corresponding large perforations (of normal sizelin the middleplate 1 1. By this expedient perfect coincidence of perforations isassured for each section separately, and any tendency of the middlestrip 14: to creep is counteracted.

lVhile the principles of construction here in described. may be embodiedin a great variety of forms of friction clutch, well known or otherwise,it is sufiicient to show one simple form of clutch operator for theparticular type of apparatus shown in Figure 1. Such an operator isillustrated in Figure 8, wherein the friction band as a whole is shownat 26, surrounding a drum 27, whose movement it controls.

The tightening and loosening of the band are carried out by meansattached to the cars '28 and 29, corresponding to the ears 12 inFigure 1. A spring 30 between'these cars is preferably supplied whichtends to force them apart.

An operating shaft 31 has one end secured to the ear 29 and extendsthrough the other ear 28 and then through a stationary bearing 32,having its other end provided with a fixed collar 33. Between thiscollar and the face of the bearing 32 is located the base of a lever 3iwhich turns loosely on the shaft 31. This lever may have a pedal at itsend for operation, as shown, or may be otherwise operated.

The ear 28 is held stationary by an extension sleeve 35 abutting uponthe bearing 32. The outer face of this hearing has a curved cam surface36, into which fits the cam surface 37 on the base of the lever. Uponswinging the lever, the cams act to force its base outward against thecollar 33, causing the shaft 31 to slide to the left, thus bringingtogether the ears 28 and 29, and tightening the band.

Return movement of the lever, restores the position shown in Figure 8,and allows the spring 30 to separate the ears and loosen the band.

Various changes may be made in this ap paratus without departing fromthe scope of this invention, which is not limited to the details hereinshown and described.

hat is claimed is-- 1. In apparatus for the purpose described, aperforated friction strip, a backing strip applied behind said frictionstrip and having perforations somewhat larger than those in the frictionstrip and registering therewith, and friction producing masses forcedthrough said perforations and allowed to swell behind them.

2. A foundation for supporting friction producing masses comprising afriction strip and a backing strip applied behind the same, said stripshaving registering perforations which are larger in the backing stripthan in the friction strip.

3. A compound friction band comprising a plurality of thin metal stripssecured together, one at least of which is resilient, andfriction-producing masses forced into the working face of the band andprojecting above its surface.

a. In apparatus as in claim 3, an inner strip of friction-metal, amiddle strip and an outer strip of resilient metal.

5. In a compound friction band, an outer strip of resilient metal, aninner perforated strip secured parallel thereto, and means between saidstrips for holding them apart while leaving a free space behind the perforations in the inner strip.

6. In a compound friction band, an outer strip of resilient metal, aninner perforated strip, an intermediate perforated strip into some ofthe perforations of which portions of the inner strip project, andrivets sec-uring the three strips together and passing through said lastnamed perforations.

7. In a compound friction band, a frictionstrip, a backing strip securedbehind thesame and rivets passmgthrough both, the edges'of the rivetholes in the frletion strip being swaged inward to form' a concaveportion fittingithe correspondlng hole in the backing strip. v

8. As inechanlcal elements for use in assemblingza compound frictionband, two thin flat metal strips having rows of perforations set atequal distances apart laterally, the perforationsin one strip beingslightly-further-apart longitudinally than in the other strip. I v Intestimony whereof I have hereto set my hand on this 4th day of May,1923.

' EDWVIN R. GILL.

